I'm using Windows XP and a brand new iPhone 4. The phone is running 4.1 and iTunes is 10.1.22. When I try to sync photos from my PC to my iPhone, I choose the folder I want to sync and press "Apply." I then get this pop-up warning:
Are you sure you want to remove 50 apps, including "Actioncam," from the iPhone "xxxxxxx's iPhone?" This will delete these apps and their data from the iPhone.
Try looking under the apps tab, and make sure you don't have them unchecked (which would take them off your phone at a sync). Once you've got everything checked off, try syncing again. Alternatively, just uncheck Sync Apps...but then you'll need to remember to sync them manually at some point.